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Bio-based thermoset polyurethane (PU) coatings comprised of polyesteramides were prepared from Gossypium arboreum (cotton seed) plant oil as a renewable source. Oil was first converted into fatty amide that was transformed into a series of polyesteramide polyols upon esterification with different dicarboxylic acids and anhydride. In the preparation of polyesteramide polyols, to increase bio-based content five different dicarboxylic acids of renewable nature were used to replace petroleum counterparts. Structures of polyols were confirmed using NMR and FT-IR spectroscopic techniques. Molecular weights of polyols were determined using gel permeation chromatography. Bio-based polyesteramide polyols were used to prepare thermoset PU by treating with aromatic diisocyanate. The thermal behavior of all prepared polyurethane coatings was determined using a thermogravimetric analyzer and differential scanning calorimeter. Coatings prepared using renewable source based polyesteramides were with high suitable curing, mechanical/chemical performances, alkali/acid resistance, and hydrophobicity. Compared to conventional PU coatings, the prepared coatings possess the superior properties such as gloss, adhesion, and pencil hardness. Thus present work demonstrates Gossypium arboreum plant oil and dicarboxylic acids as newer eco-friendly raw materials for PU coatings and compared with standard petro based polyols.

Algae are a group of photosynthetic marine or freshwater plants that exhibit high CO2 capturing capacity. Algae have been among the most promising renewable resources for overcoming climate change issues. In this study, algae oil (AO) was chemically transformed to polyols through two-step reactions and incorporated into value-added and industrially important polyurethane (PU) coatings. First, AO was reacted with diethanolamine to afford fatty amide. Then, polyetheramide polyols (AEAs) were prepared by reacting the fatty amide with bisphenol-A, 1,4-butanediol, or isosorbide. PU coatings were prepared by reaction between the AEAs and diphenylmethane diisocyanate. The PUs exhibited typical semicrystalline and three-step degradation behaviors with enhanced gel content values, supporting the high reactivity of the AEAs as polyols. The hydrophobic characteristics of the fatty acid chains of the AEAs resulted in decreased water absorption of the PUs, which improved the antimicrobial characteristics of the PUs. In particular, the PU coatings exhibited excellent resistance against alkaline aqueous media and organic solvent (xylene) along with reasonable gloss, hardness, flexibility. In saline aqueous media, the PU coatings exhibited anticorrosion performance superior to that of typical poly(tetramethylene ether) glycol-based PU coating. This study demonstrates the high potential of the PUs as anticorrosion and antimicrobial materials from the environmentally friendly renewable resource.

A series of bio-based polyester polyols with hydroxyl chain end was prepared using eugenol as a renewable source and various renewable diacids such as dimer, sebacic, succinic, and maleic acids. The functional group transformations and structure of monomer and polyols were analysed by the spectroscopic techniques. The hydroxyl functional polyester polyols were reacted with methylene diphenyl diisocyanate (MDI) to obtain polyurethane (PU) coatings. The prepared PUs were used as anticorrosive coatings and their performance was checked by dipping and electrochemical methods against 3.5 % sodium chloride (NaCl) solution. The developed coatings revealed excellent physico-mechanical properties such as transparency, gloss, flexibility, and cross-cut adhesion. Surface morphology and thermal stability of PU coatings were examined under scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis, respectively.

A series of new polyester polyols has been synthesized by the condensation reaction of epoxidized vegetable oil and poly(ethylene glycol) (PEG). Vegetable oils obtained from natural resources namely, karanja ( Pongamia glabra ) and cottonseed ( Gossypium arboreum ) were epoxidized by an eco-friendly process and further used for the preparation of polyols using PEG. The molecular weight of PEG was varied from 200 to 600 g/mol. The polyester polyols obtained were characterized by end group and spectral analysis. Eco-friendly polyurethane coatings were obtained from the synthesized polyester polyols using dipentene, a green solvent instead of xylene as a conventionally used solvent. The resultant polyurethanes were characterized by different physicochemical and thermal properties. The coating properties namely, gloss, hardness, impact resistance, adhesion, and flexibility were also evaluated and found to be useful for industrial coatings.

The use of reservoirs containing corrosion inhibitors as active substances for corrosion protection is an issue of great interest in the scientific literature. The aim of the present study is to encapsulate quinoline, a corrosion inhibitor, into a micro-reservoir to overcome disadvantages caused by its direct addition into a coating layer. Quinoline incorporated microcapsules with different core solvents were synthesized at room temperature by an interfacial polymerization method. The morphologies, wall structures, particle size and thermal properties of the synthesized microcapsules were investigated. The release study of core material was carried out by loss on drying and UV spectrophotometric methods. The prepared quinoline based microcapsules were incorporated in polyurethane (PU) coatings to study their effect on corrosion of substrate. The anticorrosive performance of coatings loaded with different weight % of microcapsules containing quinoline was tested by immersion of the PU coated mild steel specimens in 5 wt% HCl solution by visual observation and weight loss measurements.

Renewable resources used in the preparation of polymers are falling in the class of biomaterials which are rich in hydrocarbons and most of the times obtained from parts of profusely available agriculture feedstock. Use of non-edible vegetable oils and their fatty acids are currently the raw materials focused in synthesizing polymeric materials as renewable sources due to increasing economic and environmental concerns of petroleums. The current oil based polymers are prepared by consuming petroleum based anhydrides and dicarboxylic acids. With this investigation, we tried to substitute almost all components of petroleum feed stock by renewable sources in preparation of polyol. Initially palmitic acid was used as a renewable source to prepare palmitamide by amidation reaction. Further amide was converted into the polyesteramide resin (PEPAD) by reacting it with another renewable resource, i.e. dimer fatty acid which is the dimerized product of unsaturated fatty acids of vegetable oils. Structure of the prepared resin was confirmed by spectroscopic techniques and resin was also characterized by end group analysis like hydroxyl and acid values. The molecular weight of PEPAD was ranged between 2590 and 2760 g mol−1. Palmitic acid based polyesteramide was used to prepare polyurethanes by varying amount of diisocyanate. The transparent polyurethane films and coatings were obtained and examined for water absorption, contact angle, hardness, coating properties, solvent, acid and alkali resistances. The thermal properties of the polyurethane films were estimated by TGA and discussed. It was found that change in NCO content affected on transparency as well flexibility of the prepared films. It also noticed that thermal stability was shifted toward higher range by increasing mole (NCO/OH) ratios due to formation of urea linkages.

Novel two pack polyurethane wood finished coatings are prepared from renewable sources, such as vegetable oil based fatty acid and dimer fatty acid. In actual experimental part oleic acid was reacted with diethanolamine to obtain amide which was on condensation polymerization with dimer fatty acid converted into the polyesteramide polyol. These are all being used to prepare polyurethanes. The functional and structural elucidation of dimer fatty acid based polyesteramide and diethanolamide were carried out by end group analysis, spectral studies such as FTIR and 1H NMR. Average molar masses of the polyesteramide were estimated by gel permeation chromatography (GPC). The polyesteramide was used in the preparation of wood finished polyurethane coatings by reacting it with aromatic diisocyanates. Thermogravimetric analysis (TGA) was used to study the thermal behavior of coatings. Physico-chemical and coating properties of the coatings were investigated by using standard methods. The results indicated that the bio-based wood finished PU coatings provided good mechanical, weather resistance as well possessed adequate coating properties for wood surface protections.

This paper presents a study on the effect of NCO/OH ratio and an increase in hydroxyl content of acrylic polyols on the properties of polyurethane (PU) coatings. Coating properties studied are gloss, scratch resistance, flexibility and adhesion, mechanical properties include tensile strength, modulus, percent elongation and Shore hardness, while physicochemical properties include chemical resistance and solvent absorption of coated PU samples. A series of acrylic polyols (copolymers) based on butyl acrylate (BA), methyl methacrylate (MMA), styrene and 2-hydroxy ethylacrylate (HEA) were prepared by selecting different percentage of hydroxyl content. Trimer of isophorone diisocyanate (IPDI) was also synthesized in the laboratory. This trimer has trifunctionality. Isocyanurate ring of trimer increases thermal properties of PU. Polyurethanes from these acrylic polyols (containing different percent hydroxyl) and trimer of IPDI were prepared with two different NCO/OH ratios viz, 1.1:1 and 1.2:1. Polyurethanes were coated on substrates for measuring coating properties. Mechanical properties were measured on cast films of the PUs. The experimental results revealed that all polyurethane coatings based on acrylic polyols and IPDI trimer showed good gloss, scratch resistance and excellent adhesion. Thermal stability of these PU samples was found to be better. Physicochemical properties reflected that these PU have excellent chemical and solvent resistance.